Active matrix displays employ a switch at each picture element in a matrix display so that the voltage across each pixel can be controlled independently. Active matrices are especially suitable for high information content Liquid Crystal Displays (LCDs) such as LCDs used in multi-media players, cell phones, monitors and television screens.
Other types of displays that typically require a switching device at each picture element include Electrophoretic Displays (EPDs) and Rotating Element Displays. Electrophoretic displays, including displays available from companies such as E-Ink and Sipix, produce an image relying on translational movement of charged colored particles suspended in a liquid of a different color. Rotating element displays use rotational movement of optically and electrically anisotropic elements, such as bichromal spheres having a non-uniform charge distribution. Pixel performance of electrophoretic and rotating element displays can be controlled with a switching device that provides on- and off-voltages to each of the picture elements in the display matrix.
Switching devices that have been proposed for active matrix display applications include various types of Thin Film Transistors (TFTs) and Thin Film Diodes (TFDs).